The present invention relates to a printing apparatus which permits characters and/or images to be reproduced on print medium in dependence on print data and, more particularly, a so-called hybrid printing apparatus and a related control method in which the printing apparatus is composed of a plurality of printing machines that are operated in printing systems mutually different from one another.
Attempts have heretofore been made in the past for providing printing machines of various print types, that permit characters and/or images to be reproduced on print medium in dependence on print data, such as a printing machine of an ink-jet type with a print head formed with an ejection nozzle for ejecting ink onto print medium to be adhered thereto for thereby performing printing operation, or a stencil printing machine with a printing drum on which a stencil sheet made according to print data is wrapped around and which is rotated to allow ink supplied from an inside area of the printing drum to be transferred onto print medium via a perforated portion of the stencil sheet to perform the printing operation.
The printing machines of these print types have respective advantages and disadvantages. For example, the printing machine of the ink-jet type has a capability of obtaining a high resolution image of full color and, in contrast, has an issue in which a relatively longer time period is required for completing print on one sheet of print medium. Further, for instance, the stencil printing machine completes print on one sheet of print medium each time the printing drum is rotated one revolution and, so, has a capability of executing print in a short time period at an extremely low cost to be advantageous especially when performing print in a large number of prints, but encounters an issue in which, when achieving print of a colored image, printing drums of respective colors must be prepared and complex stencil making operations are required for respective colors with a resultant difficulty in performing print of the full colored image in an actual practice.
To address such an issues, it is a usual practice to selectively employ the printing machines with their suitability for particular purposes, and, for instance, when performing print in a small number of prints with the color images, the printing machine of the inkjet type is used whereas, when performing print in a large number of prints with a monocolor, the stencil printing machine is used.
In recent years, studies have been undertaken to use a so-called hybrid printing apparatus in which a plurality of printing machines of different print types are combined to take advantages of respective effects to provide a particular printing machine that is enabled to perform print in an efficient way to comply with the various purposes. A detailed technology for realizing such a hybrid printing apparatus is, for instance, disclosed in Japanese Patent Application Laid-open No. 8-197824 in which the stencil printing machine is additionally provided with a print section to execute print in the ink-jet type to enable consecutive print in the stencil printing method and the ink-jet type.
However, since the printing apparatus disclosed in the above Japanese Patent Application Laid-open No. 8-197824 has a structure in which one print section for executing print in the ink-jet type is disposed over a sheet discharge path of the print section to perform the stencil printing operation, a total print time interval is determined based on a processed time interval at the print section that executes print in the ink-jet type, resulting in an issue with no capability of fully taking an advantage of high speed print in the stencil printing machine.
As one technique to address such an issue, it is conceivable to be extremely effective to provide the stencil printing machine with a structure in which the plural printing machines of the ink-jet types, each of which has a longer print time interval than that of the stencil printing machine, are disposed in parallel to one another to permit these plural printing machines to simultaneously execute print in a parallel relationship whereupon print media, whose prints are terminated in the ink-jet processes, are then supplied to the stencil printing machine in a sequential manner to compel the stencil printing machine to consecutively perform print.
When realizing such an idealistic hybrid printing apparatus, it is important for the plural printing machines for performing print in the ink-jet process and the stencil printing machine to be maintained in an appropriate interlocking condition to appropriately control print media to be transferred so as to allow print media, whose prints have been terminated in the ink-jet process, to be transferred to the stencil printing machine in a good order.
However, when simultaneously performing print in the inkjet process in the parallel relationship with the plural printing machines and even when executing the printing operations with these printing machines based on common print data, time intervals required for the respective printing machines are not necessarily fixed owing to a difference in timings in which data is transferred to the respective printing machines or to the presence of particular services, such as a head cleaning service, to be discretely executed at irregular timings for the respective printing machines. As a result, an issue arises in which it is extremely difficult to execute control so as to transfer print media, whose prints have been terminated in the printing machines, to the stencil printing machine in a good sequential order one by one in coincidence with the timing at which print begins in the stencil printing machine.
The present invention has been completed with the above related art actual state circumstances in mind and has an object of the present invention to provide a hybrid printing apparatus and related control method for appropriately controlling delivery of print media between print sections of different print types to enable proper print at a high efficiency so as to comply with various purposes.
According to a first aspect of the present invention, there is provided a hybrid printing apparatus comprising a first print section including a plurality of printing machines which are located in parallel, a second print section including one printing machine whose printing speed is higher than that of the printing machine forming the first print section, and a medium transfer section for transferring print media from the first print section to the second print section and including a medium transfer passage having discrete passage components located in the first print section side for the plural printing machines, respectively, and collected in one passage in the second print section side, a plurality of change-over rollers disposed in the discrete passage components of the medium transfer passage, respectively, for changing over start/stop operations in transfer of print media, discharged from the respective plural printing machines, with respect to the second print section, and a plurality of medium detection sensors disposed in the discrete passage components of the medium transfer passage in close proximity to the plural change-over rollers, respectively, to detect leading edges of the print media discharged from the plural printing machines, respectively, and a control section for controlling entire operations of the printing apparatus, wherein the control section controls timings at which the plural change-over rollers are changed over in response to detection signals delivered from the plural medium detection sensors.
According to a second aspect of the present invention, there is provided a hybrid printing apparatus, wherein the control section controls the timings, at which the plural change-over rollers of the medium transfer section are changed over, so as to allow only one print medium to be transferred to the medium transfer passage of the medium transfer section.
According to a third aspect of the present invention, there is provided a hybrid printing apparatus, wherein the plural medium detection sensors of the medium transfer section are disposed at positions, that are separated from associated print medium discharge positions of the printing machines of the first print section, by values greater than the maximum dimension of the print media available for print, and the plural change-over rollers of the medium transfer section are disposed at positions between the print medium discharge positions of the printing machines of the first print section and the associated medium detection sensors, respectively.
According to a fourth aspect of the present invention, there is provided a hybrid printing apparatus, wherein the control section controls a timing, at which the print medium is supplied to the second print section, and a timing, at which the print medium, whose print has been terminated at the first print section, begins to be transferred to the second print section, in synchronism with respect to one another and controls a transfer speed of the medium transfer section such that a required transfer time interval, in which the print medium is transferred with the medium transfer section, is less than a unit print time interval of the second print section.
According to a fifth aspect of the present invention, there is provided a hybrid printing apparatus, wherein the control section controls the timings, at which the plural change-over rollers of the medium transfer section are changed over, at a time interval greater than a required transfer time interval in which the print medium is transferred with the medium transfer section.
According to a sixth aspect of the present invention, there is provided a method of controlling a hybrid printing apparatus which has a first print section including a plurality of printing machines which are located in parallel, a second print section including one printing machine whose printing speed is higher than that of the printing machine forming the first print section, and a medium transfer section for transferring print media from the first print section to the second print section and including a medium transfer passage having discrete passage components located in the first print section side for the plural printing machines, respectively, and collected in one passage in the second print section side, a plurality of change-over rollers disposed in the discrete passage components of the medium transfer passage, respectively, for changing over start/stop operations in transfer of print media, discharged from the respective plural printing machines, with respect to the second print section, and a plurality of medium detection sensors disposed in the discrete passage components of the medium transfer passage in close proximity to the plural change-over rollers, respectively, to detect leading edges of the print media discharged from the plural printing machines, respectively, the method comprising controlling timings, at which the plural change-over rollers of the medium transfer section are changed over, at a time interval greater than a required transfer time interval, in which the print medium is transferred with the medium transfer section, in response to detection signals delivered from the plural detection sensors, and controlling a timing, at which the print medium is supplied to the second print section, and a timing, at which the print medium, whose print has been terminated at the first print section, begins to be transferred to the second print section, in synchronism with respect to one another and controls a transfer speed of the medium transfer section such that a required transfer time interval, in which the print medium is transferred with the medium transfer section, is less than a unit print time interval of the second print section in response to the detection signals delivered from the detection sensors.